As I am very close to turn my boat upside down like you did the more problems arise in my head. I want to put it upside down on my existing rectangular building frame, so I have to support it with temporary cross frames out of wood across the deck and benches area. I want to be able to move it in the room together with the building frame ( has wheels ) a bit to have more work place for the side I am busy with.
Can you tell me how you supported it and did you do it exactly at frame positions ( A B C D T ) and if so at which ones. I cannot see on your pictures what you had underneath. Did you also protect the deck with pieces of carpet at these supports ?Have plenty of bricks, blocks of wood to rest the upside down boat on
I think I should not think so much about it, rather just flip it and have old car tyres at the ready like Jacques once suggested.
Greetings from Karl